When I first asked myself this question, this answer made a lot of sense :
If your app is the same as your website, then why have an app? source
But today, web apps are getting better and better, and the concept of progressive web apps is rapidly... well... progressing.
I'm working for a company that's rebuilding its entire website / mobile apps ecosystem. Our job is to sell train tickets.
Obviously you may want different UIs for your Android and iOS native apps, but beyond UI, if we're talking featurwise :
Should I strive to make sure that the native app has extra chunky chocolate chip features, or should I try to ensure that features are consistent accross apps, be they web or native ?